In an LTE (Long Term Evolution) Release-8/9 mobile communication system, a radio base station eNB is configured to transmit “MeasConfig” including “MeasObject”, “ReportConfig”, and “MeasId” to a mobile station UE.
Here, the “MeasObject” is information for designating a measurement object carrier based on RAT and a frequency, the “ReportConfig” is information for designating an event such as A1 to A5 or B1 and B2, or a transmission trigger of “Measurement Report” such as “Periodical”.
Furthermore, the “MeasId” is information for linking the “MeasObject” to the “ReportConfig” as shown in FIG. 7.
The mobile station UE is configured to perform only measurement of the “MeasObject” associated with the “ReportConfig” based on the “MeasId”.
Here, in the LTE Release-8/9 mobile communication system, when “Inter-frequency Handover (different frequency handover)” or “Inter-frequency Re-establishment (different frequency re-establishment)” has been generated, the mobile station UE is configured to autonomously switch a “MeasId” link destination.
For example, as shown in FIG. 7 and FIG. 8, when a serving cell (Serving) is changed from a cell in “F1” designated by “MeasObject#1” to a cell in “F2” designated by “MeasObject#2” by the “Inter-frequency Handover” or the “Inter-frequency Re-establishment”, the mobile station UE is configured to change a link destination of “MeasId#1” and “MeasId#2” from the “MeasObject#1” to the “MeasObject#2”, and change a link destination of “MeasId#3” and “MeasId#4” from the “MeasObject#2” to the “MeasObject#1”.
Furthermore, as shown in FIG. 7 and FIG. 9, when the serving cell (Serving) is changed from the cell in the “F1” designated by the “MeasObject#1” to a cell in “F4”, in which the “MeasObject” has not been set, by the “Inter-frequency Handover” or the “Inter-frequency Re-establishment”, the mobile station UE is configured to release the “MeasId#1” and the “MeasId#2” linked to the “MeasObject#1”.
Then, a radio base station eNB is configured to add “MeasObject#4” for designating the “F4” and link the “MeasId” to the “MeasObject#4” by “RRC Connection Reconfiguration” immediately after “Handover Command” or “Re-establishment”.
In an LTE-Advanced scheme (LTE Release-10 scheme) which is a next generation of the LTE Release-8/9 scheme, the mobile station UE is configured to be able to perform CA (Carrier Aggregation) communication with the radio base station eNB by using PCC (a Primary Component Carrier) and one or a plurality of SCCs (Secondary Component Carriers) having different carrier frequencies (EARFCN: E-UTRA Absolute Radio Frequency Channel Number).
Such a CA communication has a problem that since a serving cell exists in each PCC and each SCC, it is not possible to apply a method of switching and a method of releasing the aforementioned “MeasId”.
Therefore, the present invention has been achieved in view of the above-described problems, and an object thereof is to provide a mobile communication method and a mobile station, by which it is possible to appropriately switch and release “MeasId” in CA communication.